Allogeneic hematopoietic stem cell transplantation (HSCT) has been performed mainly for young patients due to concern about the high incidence of treatment-related mortality (TRM). Recent advances to reduce TRM by using peripheral blood stem cells or nonmyeloablative conditioning regimens have increased the age limit for this procedure, and correctly identifying the indication for transplant is essential for older patients. In this study, we analyzed data from 398 patients aged 50 or over selected from 5147 patients, who received conventional allogeneic HSCT (c-HSCT). Patients aged 50 or older showed inferior outcomes for TRM and overall survival (OS). Mulitivariate analyses confirmed that an age of 50 or over was an independent risk factor for TRM (P<0.0001) and OS (P<0.0001). Among patients aged 50 or older, increasing age remained an adverse factor for OS (P=0.0213). Regimens including total-body irradiation (TBI) correlated with a higher risk of TRM and a lower OS for older patients (P=0.0095 and 0.0303, respectively). These findings indicate that allogeneic c-HSCT should be offered to patients over 50 years only if the increased risk of TRM is acceptable, and that a non-TBI regimen is preferable when the transplant is performed.